The present invention relates to an improvement in a motor pump immersed in a fuel tank of an automobile, in particular, to an improved structure to prevent cavitation of a centrifugal pump used in high temperature circumstances or in high mountainous areas.
It has been generally experienced that when driving in a very hot area, or mountainous area higher than 2,000 meters, a great deal of vapor is sometimes generated from the central portion of a centrifugal pump impeller and filled in the pump housing so that pumping action is not made effectively due to cavitation.